What does "p.m." stand for?

Native speaker’s answer
Rebecca
The abbreviation "p.m." sometimes written as "pm" or "PM" stands for "post meridian," meaning "afternoon" to mark the time once 12:00 o'clock passes. For example, 17:00 is read as 5 p.m. Ex: I have a meeting at three p.m. today. Can you pick me up afterwards? Ex: The concert is at 7:30 PM tonight.